A multilayer ceramic capacitor (MLCC), a multilayer chip electronic component, is a chip type condenser mounted on a printed circuit board (PCB) of various electronic products such as a display device including a liquid crystal display (LCD) and a plasma display panel (PDP), a computer, a personal digital assistant (PDA), and cellular phones, to charge or discharge electricity.
Such an MLCC, having advantages such as compactness, guaranteed high capacitance, and ease in the mounting thereof may be used as a component of various electronic devices.
The MLCC may include a plurality of dielectric layers and internal electrodes, having a structure in which the internal electrodes having different polarities are alternately disposed between the dielectric layers.
The dielectric layers may have piezoelectric and electrostrictive properties. Thus, when a direct current (DC) or alternating current (AC) voltage is applied to an MLCC, a piezoelectric phenomenon may occur between the internal electrodes to cause vibrations.
Such vibrations may be transferred to a PCB on which the MLCC is mounted, through an external electrode of the MLCC, leading to the entirety of the PCB acting as an acoustically reflective surface to generate vibratory sound as noise.
Vibratory sound may correspond to audio frequencies ranging from 20 Hz to 20,000 Hz, causing listener discomfort. Such vibratory sound, which may cause listener discomfort, is commonly known as acoustic noise and research is required to reduce acoustic noise.
Japanese Patent Laid-Open Publication No. 1994-215978 discloses an MLCC in which a lower cover layer is thicker than an upper cover layer and discloses a structure in which internal electrodes are formed to be horizontal to a substrate.